1. Field of the Invention
This invention relates to a pneumatic screw aligner-feeder incorporating a screw feeder and a screw tightener.
2. Description of the Prior Art
Heretofore, there have been employed screw aligner-feeders consisting of separate screw tighteners and screw feeders which were coupled with hoses for passing screws. U.S. Pat. No. 4,114,663 falls under this category. Such a screw tightener installed separately from a screw feeder is, however, limited to the operating radius of the connecting hose.
U.S. Pat. No. 2,922,447 describes another screw aligner-feeder incorporating a screw tightener and a screw feeder. In this invention, however, screws are fed by gravity. The device is therefore useful only when used in an upright position.
A similar problem arises with the use of an aligner-feeder developed by the present inventors which is the subject of Japanese Pat. No. 31716/76. This device uses compressed air to stir screws in a container and to force them along an incline guide wall on the bottom of the container, forcing the screw to an upper output in a desired orientation.
Since the inclined guide wall is installed on the bottom of the container, use of the device is not possible at an inverted position. Therefore, when this directional screw aligner is attached to a screw tightener using compressed air as a driving source, it is still not possible to use the combined device for driving screws into a ceiling.
U.S. Pat. No. 3,247,874 describes a mechanism for orienting random screws on a chute and supplying the screws one-by-one to a screw tightener on a first-in, first-out basis. This device uses a closing shutter to separate the first screw from the following one on chute and allows the first screw to fall into a chamber which leads to a screw tightener. Because this mechanism also utilizes gravity, reliability may be poor since clogging may occur depending on the orientation of the device in use. For the above reasons, conventional screw separator-feeders and screw tighteners are separately installed and hoses generally used to couple them.